HELP... How do I fix the charger JACK?

@empebe it could be repaired by soldering a new connector to the cable. Here is the trick so, you will need to know the pinout of the connector so that the right cables get soldered into the right position. There should only be three wires in the cable

Red is VBUS

Blue is CC

Bare wire is Ground

and here is where the contacts are on the connector

credit goes here . Now you need to find the right USB-C connector

To determine where the solder points for the pins are, use a USB-C Breakout Board Test Socket. Those are available at plenty of different places.

Now if you do not have the tools or have not solder on a USB-C connector then I would suggest that you replace the charger. Yes, you can always contact Valve and inquire about a Warranty RMA but somehow I doubt that cable damage is covered.

I'd replace the charger with something like this Steam Deck Charger (US/CA)